1. Field of the Invention
The disclosed embodiments of the present invention relate to a switched capacitor circuit, and more particularly, to a switched capacitor circuit utilizing a delayed control signal and an inverting control signal for performing switching operations and related control method thereof.
2. Description of the Prior Art
In a modern communication system, a local oscillation (LO) signal is generated mainly by a voltage-controlled oscillator (VCO). Regarding a VCO including an inductor-capacitor tank (LC tank) circuit, the VCO can provide an accurate LO signal to improve the sensitivity of radio frequency (RF) transceivers due to its high quality factor and signal purity.
In general, an on-chip inductor occupies a large area. Therefore, an oscillation frequency of a VCO is varied by adjusting capacitance values in most cases, where a switched capacitor array is used to generate discrete switch capacitance values according to switch voltages. However, a junction capacitance effect may occur in a switched capacitor circuit of the switched capacitor array. Besides, when coupled to voltages of output ports, transistors in the switched capacitor circuit may turn on accidentally, thus degrading the performance of the VCO.
Thus, there is a need for an innovative circuit design, which can improve the switching quality of the switched capacitor circuit with no increase or negligible increase in the layout area, to solve the abovementioned problems.